Plier type toggle wrench

ABSTRACT

A plier type toggle wrench incorporating a novel operating connection means between the wrench lever handles and the toggle link, providing an improved closed-wrench &#39;&#39;&#39;&#39;holding&#39;&#39;&#39;&#39; effect which is responsive to relatively small manually applied forces to effect release of the toggle holding action, while at the same time being stable when in wrench-closed condition and free from violent snap-action type opening effects.

[ Dec. 17, 1974 FOREIGN PATENTS OR APPLICATIONS 610,306 12/1960Canada......................... 81/368 Primary ExaminerJames L. Jones,Jr. Attorney, Agent, or FirmBean & Bean [57] ABSTRACT A plier typetoggle wrench incorporating a novel oper- PLIER TYPE TOGGLE WRENCHInventor: Torsten F. Angquis t, Jamestown,

Assignee: Cooper Industries Inc., Houston,

Tex.

Nov. 19, 1973 Appl. No.: 417,382

United States Patent [191 Angquist [22] Filed:

g an improved holding effect which is responsive to relatively smallmanually applied forces to effect re- S m 0 14 u MMMMMM .w F g .m m Iating connection means between the wrench lever handles and the togglelink, providin closed-wrench lease of the toggle holding action, whileat the same time being stable when in wrench-closed condition and freefrom violent snap-action type opening effects.

[51] Int.

[58] Field of Search [56] References Cited UNITED STATES PATENTS2,496,308 2/1950 Pugh et PLIER TYPE TOGGLE WRENCH BACKGROUND OF THEINVENTION Toggle wrenches of the general type disclosed for example inUS. Pat. Nos. 2,280,005 and 3,710,658 have been in use for many yearsand have proved useful for performing a wide variety of operations,since these wrenches possess the advantages of being adjustable toaccommodate many differently shaped and sized workpieces, and of beingadjustable to control the amount of gripping pressure applied to thework. Further, wrenches of this type are self-locking in work-grippingposition, and are thereby operable to properly hold work-pieces inclamped condition without need for continuously applied manual pressureson the wrench.

Such wrenches typically employ over-center toggle mechanisms to maintainthe jaws in work-clamping position; but as a result thereof relativelylarge manually applied forces are required to both make and break thetoggle holding action when it is desired to clamp the wrench on awork-piece and to separate the wrench from the work. Also, such wrenchestend to snap open rather violently when the toggle action is overcome,whereby such wrenches are inconvenient if not somewhat dangerous to usedue to momentary loss of control of the operation by the user. Theseserious disadvantages of the basic type toggle wrench had led to manysuggestions for improvements, such as various type force-multiplyingdevices designed'to assist the user in making and breaking the toggleeffect; and various forms of such so-called improved toggle wrenchconstructions have been on the market for several years but have notprovided satisfactory solutions to the above stated problems.

SUMMARY OF THE INVENTION The present invention is directed towards pliertype toggle wrenches, and more particularly to an improved wrenchconstruction which provides the proper mechanical advantages for theuser when closing the wrench on a work-piece, while at the same timereducing the amount of manually applied force required to break thetoggle holding effect which maintains the wrench in work-piece clampingcondition. The toggle wrench of the present invention differs from theprior type toggle wrenches in the manner in which the toggle linkcomponent of the wrench is operably connected to the manually movablehandle lever.

More specifically, the wrench of the present invention includes a mainbody or handle having at one end a stationary work-piece engaging jaw; amovable jaw pivotally mounted upon the main handle; a fulcrum devicecarried by the other end of the main handle in positionally adjustablerelation thereon; a lever-like second handle pivotally secured to themovable jaw; and a toggle link having one end thereof coupled to thelever handle and bearing at its opposite end against the fulcrum device.

The present invention features a novel mode of restraining the togglelink member of the wrench in holding position, and from becomingaccidentally dislodged therefrom; the restraining action being attainedby means of a cam-sliding frictional engagement between the toggle linkand the lever handle. The mechanism applies maximum strains upon theoperative parts of the wrench when the wrench is closed upon awork-piece, because the toggle mechanism is then in dead-centeredcondition; but because of the present invention the mechanism isstabilized in this condition. Toggle wrench systems of the prior artdepend upon being forced into over-center positions in order to bestabilized in work-piece holding condition. Hence, they requirenon-rigid toggle mechanisms and application of relatively large manuallyapplied forces to establish and overcome their toggle-holding effects.When they are manually forced towards open" position their toggles passover dead-center position, and then snap open; being assisted in thiseffect by their jaw-opening springs. In the case of the presentinvention the wrench may be both closed and intentionally opened moreeasily and smoothly by the user; unaccompanied by any violentsnap-action type opening effects such as accompany the openings of priorart toggle-type wrenches.

In a preferred form of the present construction, the toggle control linkis connected to the lever handle by means of a pin-and-slot connection.More specifically, as shown herein, the slot is formed in the togglelink so as to be oriented and shaped to define an inclined guide surfaceagainst which the pin (which is carried by the lever handle) bears asthe toggle is being closed. Hence, the slot permits the pin to beself-centering relative to the center line of the toggle as the latteris closed incidental to frictional engagement of the cam reactionsurface of the lever handle with the cam portion of the toggle link. Thetoggle mechanism is thereby maintained in its centered" condition byfrictional engagement of the cam and the cam reactive surface, therebypreventing any unintentional opening of the wrench.

DRAWINGS The nature and mode of operation of the present invention willnow be more fully described in the following detailed description, takenwith the accompanying drawings wherein:

FIG. 1 is a side elevational view of a plier type toggle wrenchincorporating the improvement of the present invention;

FIG. 2 is a fragmentary, enlarged scale sectional view, illustrating theoperable connection between the toggle link and the lever handle whenthe wrench is in its open condition; and

FIG. 3 is a fragmentary view corresponding to FIG. 2, illustrating theoperable connection between the toggle link and the lever handle whenthe wrench is closed.

DETAILED DESCRIPTION As shown by way of example in the drawing herewith,a plier type toggle wrench of the invention may be constructed toinclude a main handle 10 having a fixed jaw 12 carried at one endthereof; an opposed, movable jaw 14 which is pivotally mounted on handle10 by suitable means such as a pivot pin 16; a fulcrum device 18 whichis adjustably mounted on handle 10; and a tension spring 20 for normallybiasing movable jaw 14 towards an open condition. An operating or leverhandle 22 is pivotally mounted on movable jaw 14 by suitable means suchas pivot pin 24.

A toggle link 26 is provided, and at one end thereof is movably coupledto handle lever 22 by means of a pin 28 (as will be explained more fullyhereinafter) and is at its other end socketed for pivotal bearingengagement with the front end of fulcrum 18. As thus far described, theconstruction is essentially similar to that disclosed for example in US.Pat. No. 2,280,005.

However, the toggle wrench of the present invention departs from theprior art in that lever handle 22 and link 26 are coupled by the pin 28carried by lever 22 in a slot 30 formed in the link 26, and in that thelink and lever handle devices are formed with cooperating friction camand cam reaction surfaces 32 and 34, respectively. As shown in FIG. 1,the fulcrum device 18 is provided in the form of a rounded end or noseportion on a screw 36 which is threaded through the end portion of themain handle 10. Thus, manual adjustments of the positionof the fulcrumwill accommodate the wrench to engagements with variously sizedworkpieces. Note that the slot 30 in the toggle link 26 provides thenecessary freedom for relative movements of the parts when the wrench isopen and/or being adjusted, while the pin 28 still operates at all timesto hold the parts in assembled relation. It is of course to beunderstood that the cam surface of link 26 and the cam bearing surface34 of lever 22 will be so shaped and dimensioned, and that the slot 30will be so located in the link 26, that when the pin 28 bottoms in theslot (incidental to closing of the wrench handles) it will force the camportion of the link 26 to slide into frictional holding bearingengagement with the inner surface 34 of the handle 22.

Thus, it will be appreciated that the frictional cam action between thetoggle link member and the lever handle of the wrench of the presentinvention develops smoothly as the latter is moved into wrench closingposition relative to the main handle. At the same time the toggle linkmoves into its dead center position. The toggle mechanism is therebystabilized when in its centered position by the cam friction effect(when the tool parts are under maximum strain) whereby the inventionprovides an important improvement over the prior art wrenches which arehighly unstable whenever they are in toggle link centered condition andare therefore awkward and inconvenient if not dangerous to use.

Thus, whereas the wrench of the present invention is stable andtherefore safer when in toggle-centered, wrench closed position, inorder to release the wrench from the workpiece holding condition it isonly necessary to overcome the frictional coupling of the toggle linkand the lever handle; the requisite force being materially less thanthat required to open an over-center toggle-locked type wrench of theprior art.

I claim:

1. In a wrench of the type having a main handle-like body portionprovided with a fixed jaw; a movable jaw pivotally mounted upon saidbody; a spring normally biasing said movable jaw toward open positionrelative to said fixed jaw; and a toggle mechanism operable for lockingsaid jaws in closed condition upon a workpiece, said toggle mechanismincluding a lever handle pivotally connected to said movable jaw and atoggle link having opposite ends thereof operably coupled to said leverhandle and pivotally bearing upon a fulcrum device carried by said body;

the improvement wherein said toggle link is operably coupled to saidlever handle by a pin-slot connection device and said link is providedwith a cam surface arranged for engagement with a cam reaction surfaceportion of said lever handle when the latter is moved in one directionto a wrench-closed position and to simultaneously shift said togglemechanism so as to arrange the pin of said pin-slot connection devicesubstantially on the center line of said toggle mechanism whereby tofrictionally lock said lever handle in said position whereat maximumjaw-locking strain is applicable upon a workpiece by the wrench parts.

2. In a wrench as set forth in claim 1, wherein the pin of said pin-slotconnection device is carried by said lever handle.

3. A plier type toggle wrench having a main handle carrying a first jawand a second jaw connected to said main handle for pivotal movementrelative to said first jaw between wrench open and closed conditions; atoggle mechanism comprising a lever handle and a toggle link pivotallyinterconnected and manually shiftable to dead-centered condition onlyfor locking said jaws in wrench closed position, and coacting means onsaid handle and said link for frictionally retaining said togglemechanism in dead-centered condition.

4. A plier type toggle wrench as set forth in claim 3, wherein a leverhandle is pivotally connected at one end to said movable jaw to providemechanical advantage to the user when opening and closing the wrench.

5. A wrench as set forth in claim 4, wherein said toggle mechanismincludes a toggle link pivotally coupled at one end to said lever handleand fulcrumed at its other end against an abutment portion of said mainhandle.

6. A wrench as set forth in claim 5, wherein said abutment portion ispositionally adjustable relative to said main handle.

7. A wrench as set forth in claim 6, wherein said toggle link is slottedand coupled to said lever handle by means of a pin slide-fitting withinthe slotted portion of said link.

8. A wrench as set forth in claim 7, wherein the wrench parts are soshaped, dimensioned and arranged that when said lever handle is moved toclose the wrench upon a work-piece the toggle mechanism moves intodead-centered condition and said link moves into aslide-friction-bearing condition relative to said lever handle, therebystabilizing the wrench in closed condition.

1. In a wrench of the type having a main handle-like body portionprovided with a fixed jaw; a movable jaw pivotally mounted upon saidbody; a spring normally biasing said movable jaw toward open positionrelative to said fixed jaw; and a toggle mechanism operable for lockingsaid jaws in closed condition upon a work-piece, said toggle mechanismincluding a lever handle pivotally connected to said movable jaw and atoggle link having opposite ends thereof operably coupled to said leverhandle and pivotally bearing upon a fulcrum device carried by said body;the improvement wherein said toggle link is operably coupled to saidlever handle by a pin-slot connection device and said link is providedwith a cam surface arranged for engagement with a cam reaction surfaceportion of said lever handle when the latter is moved in one directionto a wrench-closed position and to simultaneously shift said togglemechanism so as to arrange the pin of said pin-slot connection devicesubstantially on the center line of said toggle mechanism whereby tofrictionally lock said lever handle in said position whereat maximumjaw-locking strain is applicable upon a workpiece by the wrench parts.2. In a wrench as set forth in claim 1, wherein the pin of said pin-slotconnection device is carried by said lever handle.
 3. A plier typetoggle wrench having a main handle carrying a first jaw and a second jawconnected to said main handle for pivotal movement relative to saidfirst jaw between wrench open and closed conditions; a toggle mechanismcomprising a lever handle and a toggle link pivotally interconnected andmanually shiftable to dead-centered condition only for locking said jawsin wrench closed position, and coacting means on said handle and saidlink for frictionally retaining said toggle mechanism in dead-centeredcondition.
 4. A plier tYpe toggle wrench as set forth in claim 3,wherein a lever handle is pivotally connected at one end to said movablejaw to provide mechanical advantage to the user when opening and closingthe wrench.
 5. A wrench as set forth in claim 4, wherein said togglemechanism includes a toggle link pivotally coupled at one end to saidlever handle and fulcrumed at its other end against an abutment portionof said main handle.
 6. A wrench as set forth in claim 5, wherein saidabutment portion is positionally adjustable relative to said mainhandle.
 7. A wrench as set forth in claim 6, wherein said toggle link isslotted and coupled to said lever handle by means of a pin slide-fittingwithin the slotted portion of said link.
 8. A wrench as set forth inclaim 7, wherein the wrench parts are so shaped, dimensioned andarranged that when said lever handle is moved to close the wrench upon awork-piece the toggle mechanism moves into dead-centered condition andsaid link moves into a slide-friction-bearing condition relative to saidlever handle, thereby stabilizing the wrench in closed condition.